HTTP response time test

I cannot find anything mentioning if Hobbit/Xymon can test how long an  HTTP or HTTPS page takes to respond and alert on that.  In other  words, if a site is in a hung state so that it still technically  "responds" but it takes 5 seconds for the page to respond how does  Hobbit/Xymon handle that?  I want to make sure that if a site that we  are monitoring takes longer than a couple of seconds to load we are  alerted,

Do any of you do a test like that and how are you doing it?

Thanks,
Jason